House Speaker Nancy Pelosi of Calif., accompanied by Rep. Joaquin Castro, D-Texas, left, and others, speaks about a resolution to block President Donald Trump's emergency border security declaration on Capitol Hill, Monday, Feb. 25, 2019 in Washington. House Democrats have introduced a resolution to block the national emergency declaration that President Donald Trump issued last week to fund his long-sought wall along the U.S-Mexico border, setting up a fight that could result in Trump's first-ever veto. (AP Photo/Alex Brandon)

House Speaker Nancy Pelosi of Calif., accompanied by Rep. Joaquin Castro, D-Texas, left, and others, speaks about a resolution to block President Donald Trump's emergency border security declaration on Capitol Hill, Monday, Feb. 25, 2019 in Washington. House Democrats have introduced a resolution to block the national emergency declaration that President Donald Trump issued last week to fund his long-sought wall along the U.S-Mexico border, setting up a fight that could result in Trump's first-ever veto. (AP Photo/Alex Brandon)

WASHINGTON — Democrats ignored a veto threat and rammed legislation through the House Tuesday that would stymie President Donald Trump’s bid for billions of extra dollars for his border wall, escalating a clash over whether he was abusing his powers to advance his paramount campaign pledge.

The House’s 245-182 vote to block Trump’s national emergency declaration throws the political hot potato to the Republican-run Senate, where there were already enough GOP defections to edge it to the cusp of passage. Vice President Mike Pence used a lunch with Republican senators at the Capitol to try keeping them aboard, citing a dangerous crisis at the border, but there were no signs he’d succeeded.

“I personally couldn’t handicap the outcome at this point,” said Senate Majority Leader Mitch McConnell, R-Ky., who’s planning a vote within the next three weeks. He even said Republicans remained uncertain about the legality of Trump’s move, telling reporters, “We’re in the process of weighing that.”

Senate passage would force Trump’s first veto, which Congress would surely lack the votes to override. But the showdown was forcing Republicans to cast uncomfortable votes pitting their support for a president wildly popular with GOP voters against fears that his expansive use of emergency powers would invite future Democratic presidents to do likewise for their own pet policies.

Underscoring their desire to avoid a tally suggesting that Trump’s hold on lawmakers was weakening, House Republican leaders worked to keep the number of GOP supporters well below 53. That’s how many would be needed to reach a two-thirds majority of 288 votes, assuming all Democrats vote “yes,” the margin required for a veto override.

Thirteen House Republicans joined all voting Democrats Tuesday to support the Democratic resolution. They included moderates from competitive districts like Fred Upton of Michigan and libertarian-leaning conservatives like Thomas Massie from Kentucky.

The White House wrote to lawmakers formally threatening to veto the legislation. The letter said blocking the emergency declaration would “undermine the administration’s ability to respond effectively to the ongoing crisis at the Southern Border.”